Many direct current (DC) powered devices require a regulated DC power supply at a particular voltage or set of voltages for operation. Power sources such as alternating current (AC) line power or DC battery power, however, may not provide power that is sufficiently regulated for direct use by sensitive electronics. Moreover, many electronics operate at power levels different than those provided by the power sources.
To remedy this situation, voltage regulators can be used to convert power from a power source into regulated power of the proper voltage for a particular electronic device. In certain examples, a voltage regulator can be incorporated into a powered device, or can be a separate unit between the powered device and the power source. Many modern electronic devices use multiple voltage regulators to provide power at different levels for use by various components throughout the device.
A linear voltage regulator is one type of voltage regulator. Linear voltage regulators (also referred to herein as “linear regulators”) can be used to convert a range of voltages above a desired voltage into the desired voltage, such as by passing the voltage through an active device (e.g. transistor) and burning off the “unwanted” voltage as heat. Although linear regulators can regulate output voltages with specificity and low ripple, linear regulators can have relatively low bandwidth compared to other voltage regulators.
Charge pumps are another mechanism used to convert an input voltage of a first level into an output voltage of a second level. Charge pumps can be used to generate an output voltage of a level that is increase or decrease an input voltage.